The term angina pectoris was first used in 1772 by the British physician William Heberden when he wrote:

There is a disorder of the breast.…The seat of it, and sense of strangling and anxiety, with which it is attended, may make it not improperly be called angina pectoris. Those, who are afflicted with it, are ceased [sic] while they are walking and most particularly when they walk soon after eating, with a painful and most disagreeable sensation in the breast, which seems as it would take their breath away, if it were to increase or to continue; the moment they stand still, all this uneasiness vanishes.

Heberden’s initial description is still accurate; however, there are no truly characteristic symptoms of angina pectoris. Whereas the chest discomfort may be variously described as “constricting,” “suffocating,” “crushing,” “heavy,” or “squeezing,” there are many patients in whom the quality of the sensation is imprecise. The discomfort is usually, but not always, behind the breastbone, but pain radiating to the throat or jaw or down the inner sides of either arm is common. There may be no physical abnormalities, and an electrocardiogram may be normal or show only transient changes with exercise.

Coronary arteriography assesses the extent of coronary artery occlusion (blockage), which may vary from a small increase in coronary artery muscle tone at a partly blocked site in a branch of one of the three main coronary arteries to a 90 percent or greater blockage of the left main coronary artery with involvement of other major coronary arteries. But the extent of coronary artery disease revealed by coronary arteriography does not predicate action or treatment.

The myocardial ischemia (reduced blood supply to the heart muscle) that causes angina is due to a disturbance of the balance between heart muscle demands and supply. If demands are reduced sufficiently, the temporarily endangered supply may be adequate. The disturbance of the equilibrium may be short lived and may correct itself. Unstable angina has an appreciably worse prognosis than stable angina because of a higher risk of myocardial infarction (tissue death of a piece of the heart muscle) and sudden cardiac death, and it requires daily observation and active intervention.

When coronary arteriography reveals relatively isolated, incompletely obstructive lesions, there are two alternative treatments—medication or coronary angioplasty (balloon dilation of the localized obstruction by a special catheter). When coronary arteriography reveals a severe blockage of the left main coronary artery or proximally in one or more of the major arteries, coronary artery bypass graft surgery may be necessary.

In unstable angina pectoris, coronary arteriography may help determine whether coronary angioplasty or coronary artery bypass surgery is needed. Drugs that cause coronary dilation and peripheral arterial vasodilation (dilation of blood vessels) and that reduce the load on the heart are usually necessary. Drugs that reduce the work of the heart by blocking adrenoreceptors (receptors in the heart that respond to epinephrine) and drugs that reduce a patient’s tendency to form blood clots are given at this stage. For patients with stable angina, drugs that reduce the heart’s work are administered.

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